({{, (RefLink[UnityDimensions, paclet:ref/UnityDimensions]) 
is an option for (RefLink[UnitSimplify, paclet:ref/UnitSimplify]) that specifies which (RefLink[UnitDimensions, paclet:ref/UnitDimensions]) should be factored out.}})

OpenersNotesSection(Spacer1)Details

The default value for (RefLink[UnityDimensions, paclet:ref/UnityDimensions]) is {}.

(RefLink[UnityDimensions, paclet:ref/UnityDimensions]) specifications should be a list of base dimensions associated with a quantity or (RefLink[Automatic, paclet:ref/Automatic]). Typical dimensions include:

A (RefLink[UnityDimensions, paclet:ref/UnityDimensions]) specification of (RefLink[Automatic, paclet:ref/Automatic]) will factor out both "AngleUnit" and "SolidAngleUnit" dimensions.

(RefLink[UnitSimplify, paclet:ref/UnitSimplify]) will factor (RefLink[UnityDimensions, paclet:ref/UnityDimensions]) specifications out of unit expressions by first reducing them to their "SIBase" units.

(RefLink[UnityDimensions, paclet:ref/UnityDimensions]) can also take counting unit dimensions, such as "PersonUnit".

OpenersPrimaryExamplesSection(Spacer1)Examples  (7)

OpenersExampleSection0(Spacer1)Basic Examples  (3)

(RefLink[UnitSimplify, paclet:ref/UnitSimplify]) will not automatically cancel out angle units like "AngularDegrees":

UnitSimplify[(QuantityUnitPostfix[3, "°", "per ""minute", degrees per minute, (("AngularDegrees")/("Minutes"))])]

(RefLink[UnityDimensions, paclet:ref/UnityDimensions]) can be used to factor out angular units:

UnitSimplify[(QuantityUnitPostfix[3, "°", "per ""minute", degrees per minute, (("AngularDegrees")/("Minutes"))]),UnityDimensions->{"AngleUnit"}]

Use (RefLink[UnityDimensions, paclet:ref/UnityDimensions]) to factor "Radians" out of a unit comparison:

UnitSimplify[(Quantity[1, "J""/""rad", joules per radian, (("Joules")/("Radians"))]),UnityDimensions->{"AngleUnit"}]==(Quantity[1, "m" "N", meter newtons, "Meters" "Newtons"])

Use UnityDimensions->Automatic to remove both "AngleUnit" and "SolidAngleUnit" dimensions:

UnitSimplify[Quantity[30.2, "AngularDegrees"/"Steradians"],UnityDimensions->Automatic]

OpenersExampleSection1(Spacer1)Scope  (3)

Use (RefLink[UnityDimensions, paclet:ref/UnityDimensions]) to factor out counting units such as "People":

density = EntityValue[(Entity["France", Entity["Country","France"], "Entity[\"Country\", \"France\"]", "country"]),(EntityProperty["population density", EntityProperty["Country","PopulationDensity"], "EntityProperty[\"Country\", \"PopulationDensity\"]"])]

UnitSimplify[density,UnityDimensions->{"PersonUnit"}]

(RefLink[UnityDimensions, paclet:ref/UnityDimensions]) can include any number of dimensions to factor out:

q=Quantity[14.2,"Kilograms""Meters"^2/"Seconds"^2]

UnitSimplify[q,UnityDimensions->{"MassUnit"}]

UnitSimplify[q,UnityDimensions->{"MassUnit","TimeUnit"}]

UnitSimplify[q,UnityDimensions->{"MassUnit","LengthUnit","TimeUnit"}]

(RefLink[UnityDimensions, paclet:ref/UnityDimensions]) can factor out units that are not explicitly given:

UnitSimplify[Quantity[14.2,"Joules"],UnityDimensions->{"MassUnit","TimeUnit"}]

OpenersExampleSection3(Spacer1)Possible Issues  (1)

(RefLink[UnityDimensions, paclet:ref/UnityDimensions]) specifications are factored out by first reducing constituent units to their "SIBase" form:

UnitSimplify[Quantity[3,"Feet"],UnityDimensions->{"LengthUnit"}]

UnitSimplify[Quantity[3,"Meters"],UnityDimensions->{"LengthUnit"}]

({{DocumentationFooterIconsRelatedFunction.png, ({{See Also}, {(RefLink[UnitSimplify, paclet:ref/UnitSimplify])  ▪  (RefLink[UnitDimensions, paclet:ref/UnitDimensions])  ▪  (RefLink[QuantityVariableDimensions, paclet:ref/QuantityVariableDimensions])  ▪  (RefLink[Quantity, paclet:ref/Quantity])  ▪  (RefLink[QuantityVariable, paclet:ref/QuantityVariable])}})}})